Morphology in the Era of Large Surveys
ArXiv 1310.0556 (2013)
Abstract:
The study of galaxies has changed dramatically over the past few decades with the advent of large-scale astronomical surveys. These large collaborative efforts have made available high-quality imaging and spectroscopy of hundreds of thousands of systems, providing a body of observations which has significantly enhanced our understanding not only of cosmology and large-scale structure in the universe but also of the astrophysics of galaxy formation and evolution. Throughout these changes, one thing that has remained constant is the role of galaxy morphology as a clue to understanding galaxies. But obtaining morphologies for large numbers of galaxies is challenging; this topic, "Morphology in the era of large surveys", was the subject of a recent discussion meeting at the Royal Astronomical Society, and this "Astronomy and Geophysics" article is a report on that meeting.Diagnostics of agn-driven molecular outflows in ulirgs from herschel-pacs observations of oh at 119 μm
Astrophysical Journal 775:2 (2013)
Abstract:
We report on our observations of the 79 and 119 μm doublet transitions of OH for 24 local (z < 0.262) ULIRGs observed with Herschel-PACS as part of the Herschel ULIRG Survey (HERUS). Some OH 119 μm profiles display a clear P-Cygni shape and therefore imply outflowing OH gas, while other profiles are predominantly in absorption or are completely in emission. We find that the relative strength of the OH emission component decreases as the silicate absorption increases. This result locates the OH outflows inside the obscured nuclei. The maximum outflow velocities for our sources range from less than 100 to 2000 km s-1, with 15/24 (10/24) sources showing OH absorption at velocities exceeding 700 km s-1 (1000 km s-1). Three sources show maximum OH outflow velocities exceeding that of Mrk231. Since outflow velocities above 500-700 km s-1 are thought to require an active galactic nucleus (AGN) to drive them, about two-thirds of our ULIRG sample may host AGN-driven molecular outflows. This finding is supported by the correlation we find between the maximum OH outflow velocity and the IR-derived bolometric AGN luminosity. No such correlation is found with the IR-derived star formation rate. The highest outflow velocities are found among sources that are still deeply embedded. We speculate that the molecular outflows in these sources may be in an early phase of disrupting the nuclear dust veil before these sources evolve into less-obscured AGNs. Four of our sources show high-velocity wings in their [C II] fine-structure line profiles, implying neutral gas outflow masses of at least (2-4.5) × 108 M. © 2013. The American Astronomical Society. All rights reserved..Erratum: Indirect measurement of sin2θW (MW) using e+e- pairs in the Z-boson region with pp¯ collisions at a center-of-momentum energy of 1.96 TeV [Phys. Rev. D 88, 072002 (2013)]
Physical Review D American Physical Society (APS) 88:7 (2013) 079905
Measurement of the hadronic activity in events with a Z and two jets and extraction of the cross section for the electroweak production of a Z with two jets in pp collisions at √s = 7 TeV
Journal of High Energy Physics 2013:10 (2013)
Abstract:
The first measurement of the electroweak production cross section of a Z boson with two jets (Zjj) in pp collisions at √s = 7TeV is presented, based on a data sample recorded by the CMS experiment at the LHC with an integrated luminosity of 5fb-1. The cross section is measured for the ℓℓjj (ℓ = e, μ) final state in the kinematic region m ℓℓ > 50 GeV, mjj > 120 GeV, transverse momenta pjT > 25 GeV and pseudorapidity |ηj| < 4.0. The measurement, combining the muon and electron channels, yields σ = 154 ± 24 (stat.) ± 46 (exp. syst.) ± 27 (th. syst.) ± 3 (lum.) fb, in agreement with the theoretical cross section. The hadronic activity, in the rapidity interval between the jets, is also measured. These results establish an important foundation for the more general study of vector boson fusion processes, of relevance for Higgs boson searches and for measurements of electroweak gauge couplings and vector boson scattering.Measurement of the high-mass Drell-Yan differential cross-section in pp collisions at s=7TeV with the ATLAS detector
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 725:4-5 (2013) 223-242